Add support for local login

[hemanik]

Expected behavior

In the case of local setup, the user should be able to login with a local Oauth server instead of keycloak. With the login workflow as described below:

• UI calls Auth
• Auth responds to UI with a url as a 307
• UI asks user to login by redirecting to the url returned above.
• The local oauth server calls Auth with /code=XYZ
• ( behind the scene ) Auth calls the local oauth server to get a token by presenting the code
• Auth responds to the local oauth server with a 307 and location=localhost:3000?token=XYZ
• The local oauth sends the user to localhost:3000?token=XYZ

[sbose78]

In order of preference

1. Explore an option of 'mock' oauth server that could be run locally with minimal config --> zero code change on login side.
2. If (1) doesn't work out, run a keycloak remotely with a public client to provide login via github. --> zero code change on login side.
3. Make code changes on login side to not depend on the identity provider to return a JWT. This has long term benefits - but in the short term, i will try to avoid making any code changes.

[xcoulon]

The code for @hemanik's standalone OAuth service is at https://github.com/fabric8-services/go-oauth2-jwt

[xcoulon]

Moving to backlog as priority is lower for now.

[sbryzak]

Still a low priority as of Jan 2019